package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private RedissonClient redissonClient;
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }


    private static final ExecutorService SECKILL_ORDER_EXECUTOR= Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable{
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    //获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS stream.orders >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    //判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        //获取失败，说明没有消息，继续下一次循环
                        continue;
                    }
                    //解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //获取成功，可以下单，创建订单
                    handleVoucherOrder(voucherOrder);
                    //ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlerPendingList();
                }
            }

            }

        private void handlerPendingList() {
            while (true) {
                try {
                    //获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 STREAMS stream.orders 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName,ReadOffset.from("0"))
                    );
                    //判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        //获取失败，说明没有消息，结束循环
                        break;
                    }
                    //解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //获取成功，可以下单，创建订单
                    handleVoucherOrder(voucherOrder);
                    //ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        ex.printStackTrace();
                    }
                }
            }
        }
    }

//    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
//    private class VoucherOrderHandler implements Runnable{
//        @Override
//        public void run() {
//            while (true) {
//                //获取队列中的订单信息
//                try {
//                    VoucherOrder voucherOrder = orderTasks.take();
//                    //创建订单
//                    handleVoucherOrder(voucherOrder);
//                } catch (Exception e) {
//                    log.error("处理订单异常", e);
//                }
//            }
//
//            }
//        }

        private void handleVoucherOrder(VoucherOrder voucherOrder) {
        //获取用户id
        Long userId = voucherOrder.getUserId();
        //创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        //判断是否获取成功
        if (!isLock){
            //获取失败，返回错误信息
            log.error("不允许重复下单");
            return;
        }
        //获取代理对象
        try {
            createVoucherOrder(voucherOrder);
        } catch (IllegalStateException e) {
            throw new RuntimeException(e);
        } finally {
            //释放锁
            lock.unlock();
        }

    }

    IVoucherOrderService proxy;

    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户id
        Long userId = UserHolder.getUser().getId();
        //订单ID
        long orderId = redisIdWorker.nextId("order");
        //执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(),String.valueOf(orderId)
        );
        //判断结果是为0
        int r=result.intValue();
        if (r != 0){
            //不为0，没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }

        //获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //返回订单id
        return Result.ok(orderId);
    }

//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        //获取用户id
//        Long userId = UserHolder.getUser().getId();
//        //执行lua脚本
//        Long result = stringRedisTemplate.execute(
//                SECKILL_SCRIPT,
//                Collections.emptyList(),
//                voucherId.toString(), userId.toString()
//        );
//        //判断结果是为0
//        int r=result.intValue();
//        if (r != 0){
//            //不为0，没有购买资格
//            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
//        }
//        //为0，有购买资格,把订单信息保存阻塞队列
//            VoucherOrder voucherOrder = new VoucherOrder();
//            //订单ID
//            long orderId = redisIdWorker.nextId("order");
//            voucherOrder.setId(orderId);
//            //用户ID
//            voucherOrder.setUserId(userId);
//            //优惠券ID
//            voucherOrder.setVoucherId(voucherId);
//            //添加到阻塞队列
//            orderTasks.add(voucherOrder);
//            //获取代理对象
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            //返回订单id
//            return Result.ok(orderId);
//
//    }



//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        //查询优惠券
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        //判断秒杀是否开始
//        if (voucher.getBeginTime().isAfter(LocalDateTime.now())){
//            //尚未开始
//            return Result.fail("秒杀尚未开始");
//        }
//        //判断秒杀是否结束
//        if (voucher.getEndTime().isBefore(LocalDateTime.now())){
//            //已经结束
//            return Result.fail("秒杀已经结束");
//        }
//        //判断库存是否充足
//        if (voucher.getStock() < 1){
//            //库存不足
//            return Result.fail("库存不足");
//        }
//        Long userId = UserHolder.getUser().getId();
//        //创建锁对象
//        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//        //获取锁
//        boolean isLock = lock.tryLock();
//        //判断是否获取成功
//        if (!isLock){
//            //获取失败，返回错误信息
//           return Result.fail("不允许重复下单");
//        }
//        //获取代理对象
//        try {
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);
//        } catch (IllegalStateException e) {
//            throw new RuntimeException(e);
//        } finally {
//            //释放锁
//            lock.unlock();
//        }
//
//    }

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //一人一单判断
        Long userId = voucherOrder.getUserId();
        //查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        //判断是否存在
        if (count > 0){
            //用户已经购买过了
            log.error("用户已经购买过一次");
            return ;
        }
        //扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1") // set stock = stock - 1
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock",0)  // where id = ? and stock > 0
                .update();
        if (!success){
            log.error("库存不足");
            return ;
        }
        //创建订单
        save(voucherOrder);
    }

}
